aboutsummaryrefslogtreecommitdiff
path: root/arch/x86/kernel/ptrace.c
blob: cabdabce3cb2170e4af1d50ef46ce9a605405a90 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
/* By Ross Biro 1/23/92 */
/*
 * Pentium III FXSR, SSE support
 *	Gareth Hughes <gareth@valinux.com>, May 2000
 *
 * BTS tracing
 *	Markus Metzger <markus.t.metzger@intel.com>, Dec 2007
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/regset.h>
#include <linux/tracehook.h>
#include <linux/user.h>
#include <linux/elf.h>
#include <linux/security.h>
#include <linux/audit.h>
#include <linux/seccomp.h>
#include <linux/signal.h>
#include <linux/workqueue.h>

#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/i387.h>
#include <asm/debugreg.h>
#include <asm/ldt.h>
#include <asm/desc.h>
#include <asm/prctl.h>
#include <asm/proto.h>
#include <asm/ds.h>
#include <asm/hw_breakpoint.h>

#include <trace/syscall.h>

#include "tls.h"

enum x86_regset {
	REGSET_GENERAL,
	REGSET_FP,
	REGSET_XFP,
	REGSET_IOPERM64 = REGSET_XFP,
	REGSET_TLS,
	REGSET_IOPERM32,
};

/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */

/*
 * Determines which flags the user has access to [1 = access, 0 = no access].
 */
#define FLAG_MASK_32		((unsigned long)			\
				 (X86_EFLAGS_CF | X86_EFLAGS_PF |	\
				  X86_EFLAGS_AF | X86_EFLAGS_ZF |	\
				  X86_EFLAGS_SF | X86_EFLAGS_TF |	\
				  X86_EFLAGS_DF | X86_EFLAGS_OF |	\
				  X86_EFLAGS_RF | X86_EFLAGS_AC))

/*
 * Determines whether a value may be installed in a segment register.
 */
static inline bool invalid_selector(u16 value)
{
	return unlikely(value != 0 && (value & SEGMENT_RPL_MASK) != USER_RPL);
}

#ifdef CONFIG_X86_32

#define FLAG_MASK		FLAG_MASK_32

static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
{
	BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
	return &regs->bx + (regno >> 2);
}

static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
{
	/*
	 * Returning the value truncates it to 16 bits.
	 */
	unsigned int retval;
	if (offset != offsetof(struct user_regs_struct, gs))
		retval = *pt_regs_access(task_pt_regs(task), offset);
	else {
		if (task == current)
			retval = get_user_gs(task_pt_regs(task));
		else
			retval = task_user_gs(task);
	}
	return retval;
}

static int set_segment_reg(struct task_struct *task,
			   unsigned long offset, u16 value)
{
	/*
	 * The value argument was already truncated to 16 bits.
	 */
	if (invalid_selector(value))
		return -EIO;

	/*
	 * For %cs and %ss we cannot permit a null selector.
	 * We can permit a bogus selector as long as it has USER_RPL.
	 * Null selectors are fine for other segment registers, but
	 * we will never get back to user mode with invalid %cs or %ss
	 * and will take the trap in iret instead.  Much code relies
	 * on user_mode() to distinguish a user trap frame (which can
	 * safely use invalid selectors) from a kernel trap frame.
	 */
	switch (offset) {
	case offsetof(struct user_regs_struct, cs):
	case offsetof(struct user_regs_struct, ss):
		if (unlikely(value == 0))
			return -EIO;

	default:
		*pt_regs_access(task_pt_regs(task), offset) = value;
		break;

	case offsetof(struct user_regs_struct, gs):
		if (task == current)
			set_user_gs(task_pt_regs(task), value);
		else
			task_user_gs(task) = value;
	}

	return 0;
}

#else  /* CONFIG_X86_64 */

#define FLAG_MASK		(FLAG_MASK_32 | X86_EFLAGS_NT)

static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long offset)
{
	BUILD_BUG_ON(offsetof(struct pt_regs, r15) != 0);
	return &regs->r15 + (offset / sizeof(regs->r15));
}

static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
{
	/*
	 * Returning the value truncates it to 16 bits.
	 */
	unsigned int seg;

	switch (offset) {
	case offsetof(struct user_regs_struct, fs):
		if (task == current) {
			/* Older gas can't assemble movq %?s,%r?? */
			asm("movl %%fs,%0" : "=r" (seg));
			return seg;
		}
		return task->thread.fsindex;
	case offsetof(struct user_regs_struct, gs):
		if (task == current) {
			asm("movl %%gs,%0" : "=r" (seg));
			return seg;
		}
		return task->thread.gsindex;
	case offsetof(struct user_regs_struct, ds):
		if (task == current) {
			asm("movl %%ds,%0" : "=r" (seg));
			return seg;
		}
		return task->thread.ds;
	case offsetof(struct user_regs_struct, es):
		if (task == current) {
			asm("movl %%es,%0" : "=r" (seg));
			return seg;
		}
		return task->thread.es;

	case offsetof(struct user_regs_struct, cs):
	case offsetof(struct user_regs_struct, ss):
		break;
	}
	return *pt_regs_access(task_pt_regs(task), offset);
}

static int set_segment_reg(struct task_struct *task,
			   unsigned long offset, u16 value)
{
	/*
	 * The value argument was already truncated to 16 bits.
	 */
	if (invalid_selector(value))
		return -EIO;

	switch (offset) {
	case offsetof(struct user_regs_struct,fs):
		/*
		 * If this is setting fs as for normal 64-bit use but
		 * setting fs_base has implicitly changed it, leave it.
		 */
		if ((value == FS_TLS_SEL && task->thread.fsindex == 0 &&
		     task->thread.fs != 0) ||
		    (value == 0 && task->thread.fsindex == FS_TLS_SEL &&
		     task->thread.fs == 0))
			break;
		task->thread.fsindex = value;
		if (task == current)
			loadsegment(fs, task->thread.fsindex);
		break;
	case offsetof(struct user_regs_struct,gs):
		/*
		 * If this is setting gs as for normal 64-bit use but
		 * setting gs_base has implicitly changed it, leave it.
		 */
		if ((value == GS_TLS_SEL && task->thread.gsindex == 0 &&
		     task->thread.gs != 0) ||
		    (value == 0 && task->thread.gsindex == GS_TLS_SEL &&
		     task->thread.gs == 0))
			break;
		task->thread.gsindex = value;
		if (task == current)
			load_gs_index(task->thread.gsindex);
		break;
	case offsetof(struct user_regs_struct,ds):
		task->thread.ds = value;
		if (task == current)
			loadsegment(ds, task->thread.ds);
		break;
	case offsetof(struct user_regs_struct,es):
		task->thread.es = value;
		if (task == current)
			loadsegment(es, task->thread.es);
		break;

		/*
		 * Can't actually change these in 64-bit mode.
		 */
	case offsetof(struct user_regs_struct,cs):
		if (unlikely(value == 0))
			return -EIO;
#ifdef CONFIG_IA32_EMULATION
		if (test_tsk_thread_flag(task, TIF_IA32))
			task_pt_regs(task)->cs = value;
#endif
		break;
	case offsetof(struct user_regs_struct,ss):
		if (unlikely(value == 0))
			return -EIO;
#ifdef CONFIG_IA32_EMULATION
		if (test_tsk_thread_flag(task, TIF_IA32))
			task_pt_regs(task)->ss = value;
#endif
		break;
	}

	return 0;
}

#endif	/* CONFIG_X86_32 */

static unsigned long get_flags(struct task_struct *task)
{
	unsigned long retval = task_pt_regs(task)->flags;

	/*
	 * If the debugger set TF, hide it from the readout.
	 */
	if (test_tsk_thread_flag(task, TIF_FORCED_TF))
		retval &= ~X86_EFLAGS_TF;

	return retval;
}

static int set_flags(struct task_struct *task, unsigned long value)
{
	struct pt_regs *regs = task_pt_regs(task);

	/*
	 * If the user value contains TF, mark that
	 * it was not "us" (the debugger) that set it.
	 * If not, make sure it stays set if we had.
	 */
	if (value & X86_EFLAGS_TF)
		clear_tsk_thread_flag(task, TIF_FORCED_TF);
	else if (test_tsk_thread_flag(task, TIF_FORCED_TF))
		value |= X86_EFLAGS_TF;

	regs->flags = (regs->flags & ~FLAG_MASK) | (value & FLAG_MASK);

	return 0;
}

static int putreg(struct task_struct *child,
		  unsigned long offset, unsigned long value)
{
	switch (offset) {
	case offsetof(struct user_regs_struct, cs):
	case offsetof(struct user_regs_struct, ds):
	case offsetof(struct user_regs_struct, es):
	case offsetof(struct user_regs_struct, fs):
	case offsetof(struct user_regs_struct, gs):
	case offsetof(struct user_regs_struct, ss):
		return set_segment_reg(child, offset, value);

	case offsetof(struct user_regs_struct, flags):
		return set_flags(child, value);

#ifdef CONFIG_X86_64
	/*
	 * Orig_ax is really just a flag with small positive and
	 * negative values, so make sure to always sign-extend it
	 * from 32 bits so that it works correctly regardless of
	 * whether we come from a 32-bit environment or not.
	 */
	case offsetof(struct user_regs_struct, orig_ax):
		value = (long) (s32) value;
		break;

	case offsetof(struct user_regs_struct,fs_base):
		if (value >= TASK_SIZE_OF(child))
			return -EIO;
		/*
		 * When changing the segment base, use do_arch_prctl
		 * to set either thread.fs or thread.fsindex and the
		 * corresponding GDT slot.
		 */
		if (child->thread.fs != value)
			return do_arch_prctl(child, ARCH_SET_FS, value);
		return 0;
	case offsetof(struct user_regs_struct,gs_base):
		/*
		 * Exactly the same here as the %fs handling above.
		 */
		if (value >= TASK_SIZE_OF(child))
			return -EIO;
		if (child->thread.gs != value)
			return do_arch_prctl(child, ARCH_SET_GS, value);
		return 0;
#endif
	}

	*pt_regs_access(task_pt_regs(child), offset) = value;
	return 0;
}

static unsigned long getreg(struct task_struct *task, unsigned long offset)
{
	switch (offset) {
	case offsetof(struct user_regs_struct, cs):
	case offsetof(struct user_regs_struct, ds):
	case offsetof(struct user_regs_struct, es):
	case offsetof(struct user_regs_struct, fs):
	case offsetof(struct user_regs_struct, gs):
	case offsetof(struct user_regs_struct, ss):
		return get_segment_reg(task, offset);

	case offsetof(struct user_regs_struct, flags):
		return get_flags(task);

#ifdef CONFIG_X86_64
	case offsetof(struct user_regs_struct, fs_base): {
		/*
		 * do_arch_prctl may have used a GDT slot instead of
		 * the MSR.  To userland, it appears the same either
		 * way, except the %fs segment selector might not be 0.
		 */
		unsigned int seg = task->thread.fsindex;
		if (task->thread.fs != 0)
			return task->thread.fs;
		if (task == current)
			asm("movl %%fs,%0" : "=r" (seg));
		if (seg != FS_TLS_SEL)
			return 0;
		return get_desc_base(&task->thread.tls_array[FS_TLS]);
	}
	case offsetof(struct user_regs_struct, gs_base): {
		/*
		 * Exactly the same here as the %fs handling above.
		 */
		unsigned int seg = task->thread.gsindex;
		if (task->thread.gs != 0)
			return task->thread.gs;
		if (task == current)
			asm("movl %%gs,%0" : "=r" (seg));
		if (seg != GS_TLS_SEL)
			return 0;
		return get_desc_base(&task->thread.tls_array[GS_TLS]);
	}
#endif
	}

	return *pt_regs_access(task_pt_regs(task), offset);
}

static int genregs_get(struct task_struct *target,
		       const struct user_regset *regset,
		       unsigned int pos, unsigned int count,
		       void *kbuf, void __user *ubuf)
{
	if (kbuf) {
		unsigned long *k = kbuf;
		while (count > 0) {
			*k++ = getreg(target, pos);
			count -= sizeof(*k);
			pos += sizeof(*k);
		}
	} else {
		unsigned long __user *u = ubuf;
		while (count > 0) {
			if (__put_user(getreg(target, pos), u++))
				return -EFAULT;
			count -= sizeof(*u);
			pos += sizeof(*u);
		}
	}

	return 0;
}

static int genregs_set(struct task_struct *target,
		       const struct user_regset *regset,
		       unsigned int pos, unsigned int count,
		       const void *kbuf, const void __user *ubuf)
{
	int ret = 0;
	if (kbuf) {
		const unsigned long *k = kbuf;
		while (count > 0 && !ret) {
			ret = putreg(target, pos, *k++);
			count -= sizeof(*k);
			pos += sizeof(*k);
		}
	} else {
		const unsigned long  __user *u = ubuf;
		while (count > 0 && !ret) {
			unsigned long word;
			ret = __get_user(word, u++);
			if (ret)
				break;
			ret = putreg(target, pos, word);
			count -= sizeof(*u);
			pos += sizeof(*u);
		}
	}
	return ret;
}

/*
 * Decode the length and type bits for a particular breakpoint as
 * stored in debug register 7.  Return the "enabled" status.
 */
static int decode_dr7(unsigned long dr7, int bpnum, unsigned *len,
		unsigned *type)
{
	int bp_info = dr7 >> (DR_CONTROL_SHIFT + bpnum * DR_CONTROL_SIZE);

	*len = (bp_info & 0xc) | 0x40;
	*type = (bp_info & 0x3) | 0x80;
	return (dr7 >> (bpnum * DR_ENABLE_SIZE)) & 0x3;
}

static void ptrace_triggered(struct hw_breakpoint *bp, struct pt_regs *regs)
{
	struct thread_struct *thread = &(current->thread);
	int i;

	/*
	 * Store in the virtual DR6 register the fact that the breakpoint
	 * was hit so the thread's debugger will see it.
	 */
	for (i = 0; i < hbp_kernel_pos; i++)
		/*
		 * We will check bp->info.address against the address stored in
		 * thread's hbp structure and not debugreg[i]. This is to ensure
		 * that the corresponding bit for 'i' in DR7 register is enabled
		 */
		if (bp->info.address == thread->hbp[i]->info.address)
			break;

	thread->debugreg6 |= (DR_TRAP0 << i);
}

/*
 * Handle ptrace writes to debug register 7.
 */
static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
{
	struct thread_struct *thread = &(tsk->thread);
	unsigned long old_dr7 = thread->debugreg7;
	int i, orig_ret = 0, rc = 0;
	int enabled, second_pass = 0;
	unsigned len, type;
	struct hw_breakpoint *bp;

	data &= ~DR_CONTROL_RESERVED;
restore:
	/*
	 * Loop through all the hardware breakpoints, making the
	 * appropriate changes to each.
	 */
	for (i = 0; i < HBP_NUM; i++) {
		enabled = decode_dr7(data, i, &len, &type);
		bp = thread->hbp[i];

		if (!enabled) {
			if (bp) {
				/* Don't unregister the breakpoints right-away,
				 * unless all register_user_hw_breakpoint()
				 * requests have succeeded. This prevents
				 * any window of opportunity for debug
				 * register grabbing by other users.
				 */
				if (!second_pass)
					continue;
				unregister_user_hw_breakpoint(tsk, bp);
				kfree(bp);
			}
			continue;
		}
		if (!bp) {
			rc = -ENOMEM;
			bp = kzalloc(sizeof(struct hw_breakpoint), GFP_KERNEL);
			if (bp) {
				bp->info.address = thread->debugreg[i];
				bp->triggered = ptrace_triggered;
				bp->info.len = len;
				bp->info.type = type;
				rc = register_user_hw_breakpoint(tsk, bp);
				if (rc)
					kfree(bp);
			}
		} else
			rc = modify_user_hw_breakpoint(tsk, bp);
		if (rc)
			break;
	}
	/*
	 * Make a second pass to free the remaining unused breakpoints
	 * or to restore the original breakpoints if an error occurred.
	 */
	if (!second_pass) {
		second_pass = 1;
		if (rc < 0) {
			orig_ret = rc;
			data = old_dr7;
		}
		goto restore;
	}
	return ((orig_ret < 0) ? orig_ret : rc);
}

/*
 * Handle PTRACE_PEEKUSR calls for the debug register area.
 */
static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
{
	struct thread_struct *thread = &(tsk->thread);
	unsigned long val = 0;

	if (n < HBP_NUM)
		val = thread->debugreg[n];
	else if (n == 6)
		val = thread->debugreg6;
	else if (n == 7)
		val = thread->debugreg7;
	return val;
}

/*
 * Handle PTRACE_POKEUSR calls for the debug register area.
 */
int ptrace_set_debugreg(struct task_struct *tsk, int n, unsigned long val)
{
	struct thread_struct *thread = &(tsk->thread);
	int rc = 0;

	/* There are no DR4 or DR5 registers */
	if (n == 4 || n == 5)
		return -EIO;

	if (n == 6) {
		tsk->thread.debugreg6 = val;
		goto ret_path;
	}
	if (n < HBP_NUM) {
		if (thread->hbp[n]) {
			if (arch_check_va_in_userspace(val,
					thread->hbp[n]->info.len) == 0) {
				rc = -EIO;
				goto ret_path;
			}
			thread->hbp[n]->info.address = val;
		}
		thread->debugreg[n] = val;
	}
	/* All that's left is DR7 */
	if (n == 7)
		rc = ptrace_write_dr7(tsk, val);

ret_path:
	return rc;
}

/*
 * These access the current or another (stopped) task's io permission
 * bitmap for debugging or core dump.
 */
static int ioperm_active(struct task_struct *target,
			 const struct user_regset *regset)
{
	return target->thread.io_bitmap_max / regset->size;
}

static int ioperm_get(struct task_struct *target,
		      const struct user_regset *regset,
		      unsigned int pos, unsigned int count,
		      void *kbuf, void __user *ubuf)
{
	if (!target->thread.io_bitmap_ptr)
		return -ENXIO;

	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
				   target->thread.io_bitmap_ptr,
				   0, IO_BITMAP_BYTES);
}

#ifdef CONFIG_X86_PTRACE_BTS
/*
 * A branch trace store context.
 *
 * Contexts may only be installed by ptrace_bts_config() and only for
 * ptraced tasks.
 *
 * Contexts are destroyed when the tracee is detached from the tracer.
 * The actual destruction work requires interrupts enabled, so the
 * work is deferred and will be scheduled during __ptrace_unlink().
 *
 * Contexts hold an additional task_struct reference on the traced
 * task, as well as a reference on the tracer's mm.
 *
 * Ptrace already holds a task_struct for the duration of ptrace operations,
 * but since destruction is deferred, it may be executed after both
 * tracer and tracee exited.
 */
struct bts_context {
	/* The branch trace handle. */
	struct bts_tracer	*tracer;

	/* The buffer used to store the branch trace and its size. */
	void			*buffer;
	unsigned int		size;

	/* The mm that paid for the above buffer. */
	struct mm_struct	*mm;

	/* The task this context belongs to. */
	struct task_struct	*task;

	/* The signal to send on a bts buffer overflow. */
	unsigned int		bts_ovfl_signal;

	/* The work struct to destroy a context. */
	struct work_struct	work;
};

static int alloc_bts_buffer(struct bts_context *context, unsigned int size)
{
	void *buffer = NULL;
	int err = -ENOMEM;

	err = account_locked_memory(current->mm, current->signal->rlim, size);
	if (err < 0)
		return err;

	buffer = kzalloc(size, GFP_KERNEL);
	if (!buffer)
		goto out_refund;

	context->buffer = buffer;
	context->size = size;
	context->mm = get_task_mm(current);

	return 0;

 out_refund:
	refund_locked_memory(current->mm, size);
	return err;
}

static inline void free_bts_buffer(struct bts_context *context)
{
	if (!context->buffer)
		return;

	kfree(context->buffer);
	context->buffer = NULL;

	refund_locked_memory(context->mm, context->size);
	context->size = 0;

	mmput(context->mm);
	context->mm = NULL;
}

static void free_bts_context_work(struct work_struct *w)
{
	struct bts_context *context;

	context = container_of(w, struct bts_context, work);

	ds_release_bts(context->tracer);
	put_task_struct(context->task);
	free_bts_buffer(context);
	kfree(context);
}

static inline void free_bts_context(struct bts_context *context)
{
	INIT_WORK(&context->work, free_bts_context_work);
	schedule_work(&context->work);
}

static inline struct bts_context *alloc_bts_context(struct task_struct *task)
{
	struct bts_context *context = kzalloc(sizeof(*context), GFP_KERNEL);
	if (context) {
		context->task = task;
		task->bts = context;

		get_task_struct(task);
	}

	return context;
}

static int ptrace_bts_read_record(struct task_struct *child, size_t index,
				  struct bts_struct __user *out)
{
	struct bts_context *context;
	const struct bts_trace *trace;
	struct bts_struct bts;
	const unsigned char *at;
	int error;

	context = child->bts;
	if (!context)
		return -ESRCH;

	trace = ds_read_bts(context->tracer);
	if (!trace)
		return -ESRCH;

	at = trace->ds.top - ((index + 1) * trace->ds.size);
	if ((void *)at < trace->ds.begin)
		at += (trace->ds.n * trace->ds.size);

	if (!trace->read)
		return -EOPNOTSUPP;

	error = trace->read(context->tracer, at, &bts);
	if (error < 0)
		return error;

	if (copy_to_user(out, &bts, sizeof(bts)))
		return -EFAULT;

	return sizeof(bts);
}

static int ptrace_bts_drain(struct task_struct *child,
			    long size,
			    struct bts_struct __user *out)
{
	struct bts_context *context;
	const struct bts_trace *trace;
	const unsigned char *at;
	int error, drained = 0;

	context = child->bts;
	if (!context)
		return -ESRCH;

	trace = ds_read_bts(context->tracer);
	if (!trace)
		return -ESRCH;

	if (!trace->read)
		return -EOPNOTSUPP;

	if (size < (trace->ds.top - trace->ds.begin))
		return -EIO;

	for (at = trace->ds.begin; (void *)at < trace->ds.top;
	     out++, drained++, at += trace->ds.size) {
		struct bts_struct bts;

		error = trace->read(context->tracer, at, &bts);
		if (error < 0)
			return error;

		if (copy_to_user(out, &bts, sizeof(bts)))
			return -EFAULT;
	}

	memset(trace->ds.begin, 0, trace->ds.n * trace->ds.size);

	error = ds_reset_bts(context->tracer);
	if (error < 0)
		return error;

	return drained;
}

static int ptrace_bts_config(struct task_struct *child,
			     long cfg_size,
			     const struct ptrace_bts_config __user *ucfg)
{
	struct bts_context *context;
	struct ptrace_bts_config cfg;
	unsigned int flags = 0;

	if (cfg_size < sizeof(cfg))
		return -EIO;

	if (copy_from_user(&cfg, ucfg, sizeof(cfg)))
		return -EFAULT;

	context = child->bts;
	if (!context)
		context = alloc_bts_context(child);
	if (!context)
		return -ENOMEM;

	if (cfg.flags & PTRACE_BTS_O_SIGNAL) {
		if (!cfg.signal)
			return -EINVAL;

		return -EOPNOTSUPP;
		context->bts_ovfl_signal = cfg.signal;
	}

	ds_release_bts(context->tracer);
	context->tracer = NULL;

	if ((cfg.flags & PTRACE_BTS_O_ALLOC) && (cfg.size != context->size)) {
		int err;

		free_bts_buffer(context);
		if (!cfg.size)
			return 0;

		err = alloc_bts_buffer(context, cfg.size);
		if (err < 0)
			return err;
	}

	if (cfg.flags & PTRACE_BTS_O_TRACE)
		flags |= BTS_USER;

	if (cfg.flags & PTRACE_BTS_O_SCHED)
		flags |= BTS_TIMESTAMPS;

	context->tracer =
		ds_request_bts_task(child, context->buffer, context->size,
				    NULL, (size_t)-1, flags);
	if (unlikely(IS_ERR(context->tracer))) {
		int error = PTR_ERR(context->tracer);

		free_bts_buffer(context);
		context->tracer = NULL;
		return error;
	}

	return sizeof(cfg);
}

static int ptrace_bts_status(struct task_struct *child,
			     long cfg_size,
			     struct ptrace_bts_config __user *ucfg)
{
	struct bts_context *context;
	const struct bts_trace *trace;
	struct ptrace_bts_config cfg;

	context = child->bts;
	if (!context)
		return -ESRCH;

	if (cfg_size < sizeof(cfg))
		return -EIO;

	trace = ds_read_bts(context->tracer);
	if (!trace)
		return -ESRCH;

	memset(&cfg, 0, sizeof(cfg));
	cfg.size	= trace->ds.end - trace->ds.begin;
	cfg.signal	= context->bts_ovfl_signal;
	cfg.bts_size	= sizeof(struct bts_struct);

	if (cfg.signal)
		cfg.flags |= PTRACE_BTS_O_SIGNAL;

	if (trace->ds.flags & BTS_USER)
		cfg.flags |= PTRACE_BTS_O_TRACE;

	if (trace->ds.flags & BTS_TIMESTAMPS)
		cfg.flags |= PTRACE_BTS_O_SCHED;

	if (copy_to_user(ucfg, &cfg, sizeof(cfg)))
		return -EFAULT;

	return sizeof(cfg);
}

static int ptrace_bts_clear(struct task_struct *child)
{
	struct bts_context *context;
	const struct bts_trace *trace;

	context = child->bts;
	if (!context)
		return -ESRCH;

	trace = ds_read_bts(context->tracer);
	if (!trace)
		return -ESRCH;

	memset(trace->ds.begin, 0, trace->ds.n * trace->ds.size);

	return ds_reset_bts(context->tracer);
}

static int ptrace_bts_size(struct task_struct *child)
{
	struct bts_context *context;
	const struct bts_trace *trace;

	context = child->bts;
	if (!context)
		return -ESRCH;

	trace = ds_read_bts(context->tracer);
	if (!trace)
		return -ESRCH;

	return (trace->ds.top - trace->ds.begin) / trace->ds.size;
}

/*
 * Called from __ptrace_unlink() after the child has been moved back
 * to its original parent.
 */
void ptrace_bts_untrace(struct task_struct *child)
{
	if (unlikely(child->bts)) {
		free_bts_context(child->bts);
		child->bts = NULL;
	}
}
#endif /* CONFIG_X86_PTRACE_BTS */

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure the single step bit is not set.
 */
void ptrace_disable(struct task_struct *child)
{
	user_disable_single_step(child);
#ifdef TIF_SYSCALL_EMU
	clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
#endif
}

#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
static const struct user_regset_view user_x86_32_view; /* Initialized below. */
#endif

long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
	int ret;
	unsigned long __user *datap = (unsigned long __user *)data;

	switch (request) {
	/* read the word at location addr in the USER area. */
	case PTRACE_PEEKUSR: {
		unsigned long tmp;

		ret = -EIO;
		if ((addr & (sizeof(data) - 1)) || addr < 0 ||
		    addr >= sizeof(struct user))
			break;

		tmp = 0;  /* Default return condition */
		if (addr < sizeof(struct user_regs_struct))
			tmp = getreg(child, addr);
		else if (addr >= offsetof(struct user, u_debugreg[0]) &&
			 addr <= offsetof(struct user, u_debugreg[7])) {
			addr -= offsetof(struct user, u_debugreg[0]);
			tmp = ptrace_get_debugreg(child, addr / sizeof(data));
		}
		ret = put_user(tmp, datap);
		break;
	}

	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
		ret = -EIO;
		if ((addr & (sizeof(data) - 1)) || addr < 0 ||
		    addr >= sizeof(struct user))
			break;

		if (addr < sizeof(struct user_regs_struct))
			ret = putreg(child, addr, data);
		else if (addr >= offsetof(struct user, u_debugreg[0]) &&
			 addr <= offsetof(struct user, u_debugreg[7])) {
			addr -= offsetof(struct user, u_debugreg[0]);
			ret = ptrace_set_debugreg(child,
						  addr / sizeof(data), data);
		}
		break;

	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
		return copy_regset_to_user(child,
					   task_user_regset_view(current),
					   REGSET_GENERAL,
					   0, sizeof(struct user_regs_struct),
					   datap);

	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
		return copy_regset_from_user(child,
					     task_user_regset_view(current),
					     REGSET_GENERAL,
					     0, sizeof(struct user_regs_struct),
					     datap);

	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
		return copy_regset_to_user(child,
					   task_user_regset_view(current),
					   REGSET_FP,
					   0, sizeof(struct user_i387_struct),
					   datap);

	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
		return copy_regset_from_user(child,
					     task_user_regset_view(current),
					     REGSET_FP,
					     0, sizeof(struct user_i387_struct),
					     datap);

#ifdef CONFIG_X86_32
	case PTRACE_GETFPXREGS:	/* Get the child extended FPU state. */
		return copy_regset_to_user(child, &user_x86_32_view,
					   REGSET_XFP,
					   0, sizeof(struct user_fxsr_struct),
					   datap) ? -EIO : 0;

	case PTRACE_SETFPXREGS:	/* Set the child extended FPU state. */
		return copy_regset_from_user(child, &user_x86_32_view,
					     REGSET_XFP,
					     0, sizeof(struct user_fxsr_struct),
					     datap) ? -EIO : 0;
#endif

#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
	case PTRACE_GET_THREAD_AREA:
		if (addr < 0)
			return -EIO;
		ret = do_get_thread_area(child, addr,
					 (struct user_desc __user *) data);
		break;

	case PTRACE_SET_THREAD_AREA:
		if (addr < 0)
			return -EIO;
		ret = do_set_thread_area(child, addr,
					 (struct user_desc __user *) data, 0);
		break;
#endif

#ifdef CONFIG_X86_64
		/* normal 64bit interface to access TLS data.
		   Works just like arch_prctl, except that the arguments
		   are reversed. */
	case PTRACE_ARCH_PRCTL:
		ret = do_arch_prctl(child, data, addr);
		break;
#endif

	/*
	 * These bits need more cooking - not enabled yet:
	 */
#ifdef CONFIG_X86_PTRACE_BTS
	case PTRACE_BTS_CONFIG:
		ret = ptrace_bts_config
			(child, data, (struct ptrace_bts_config __user *)addr);
		break;

	case PTRACE_BTS_STATUS:
		ret = ptrace_bts_status
			(child, data, (struct ptrace_bts_config __user *)addr);
		break;

	case PTRACE_BTS_SIZE:
		ret = ptrace_bts_size(child);
		break;

	case PTRACE_BTS_GET:
		ret = ptrace_bts_read_record
			(child, data, (struct bts_struct __user *) addr);
		break;

	case PTRACE_BTS_CLEAR:
		ret = ptrace_bts_clear(child);
		break;

	case PTRACE_BTS_DRAIN:
		ret = ptrace_bts_drain
			(child, data, (struct bts_struct __user *) addr);
		break;
#endif /* CONFIG_X86_PTRACE_BTS */

	default:
		ret = ptrace_request(child, request, addr, data);
		break;
	}

	return ret;
}

#ifdef CONFIG_IA32_EMULATION

#include <linux/compat.h>
#include <linux/syscalls.h>
#include <asm/ia32.h>
#include <asm/user32.h>

#define R32(l,q)							\
	case offsetof(struct user32, regs.l):				\
		regs->q = value; break

#define SEG32(rs)							\
	case offsetof(struct user32, regs.rs):				\
		return set_segment_reg(child,				\
				       offsetof(struct user_regs_struct, rs), \
				       value);				\
		break

static int putreg32(struct task_struct *child, unsigned regno, u32 value)
{
	struct pt_regs *regs = task_pt_regs(child);

	switch (regno) {

	SEG32(cs);
	SEG32(ds);
	SEG32(es);
	SEG32(fs);
	SEG32(gs);
	SEG32(ss);

	R32(ebx, bx);
	R32(ecx, cx);
	R32(edx, dx);
	R32(edi, di);
	R32(esi, si);
	R32(ebp, bp);
	R32(eax, ax);
	R32(eip, ip);
	R32(esp, sp);

	case offsetof(struct user32, regs.orig_eax):
		/*
		 * Sign-extend the value so that orig_eax = -1
		 * causes (long)orig_ax < 0 tests to fire correctly.
		 */
		regs->orig_ax = (long) (s32) value;
		break;

	case offsetof(struct user32, regs.eflags):
		return set_flags(child, value);

	case offsetof(struct user32, u_debugreg[0]) ...
		offsetof(struct user32, u_debugreg[7]):
		regno -= offsetof(struct user32, u_debugreg[0]);
		return ptrace_set_debugreg(child, regno / 4, value);

	default:
		if (regno > sizeof(struct user32) || (regno & 3))
			return -EIO;

		/*
		 * Other dummy fields in the virtual user structure
		 * are ignored
		 */
		break;
	}
	return 0;
}

#undef R32
#undef SEG32

#define R32(l,q)							\
	case offsetof(struct user32, regs.l):				\
		*val = regs->q; break

#define SEG32(rs)							\
	case offsetof(struct user32, regs.rs):				\
		*val = get_segment_reg(child,				\
				       offsetof(struct user_regs_struct, rs)); \
		break

static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
{
	struct pt_regs *regs = task_pt_regs(child);

	switch (regno) {

	SEG32(ds);
	SEG32(es);
	SEG32(fs);
	SEG32(gs);

	R32(cs, cs);
	R32(ss, ss);
	R32(ebx, bx);
	R32(ecx, cx);
	R32(edx, dx);
	R32(edi, di);
	R32(esi, si);
	R32(ebp, bp);
	R32(eax, ax);
	R32(orig_eax, orig_ax);
	R32(eip, ip);
	R32(esp, sp);

	case offsetof(struct user32, regs.eflags):
		*val = get_flags(child);
		break;

	case offsetof(struct user32, u_debugreg[0]) ...
		offsetof(struct user32, u_debugreg[7]):
		regno -= offsetof(struct user32, u_debugreg[0]);
		*val = ptrace_get_debugreg(child, regno / 4);
		break;

	default:
		if (regno > sizeof(struct user32) || (regno & 3))
			return -EIO;

		/*
		 * Other dummy fields in the virtual user structure
		 * are ignored
		 */
		*val = 0;
		break;
	}
	return 0;
}

#undef R32
#undef SEG32

static int genregs32_get(struct task_struct *target,
			 const struct user_regset *regset,
			 unsigned int pos, unsigned int count,
			 void *kbuf, void __user *ubuf)
{
	if (kbuf) {
		compat_ulong_t *k = kbuf;
		while (count > 0) {
			getreg32(target, pos, k++);
			count -= sizeof(*k);
			pos += sizeof(*k);
		}
	} else {
		compat_ulong_t __user *u = ubuf;
		while (count > 0) {
			compat_ulong_t word;
			getreg32(target, pos, &word);
			if (__put_user(word, u++))
				return -EFAULT;
			count -= sizeof(*u);
			pos += sizeof(*u);
		}
	}

	return 0;
}

static int genregs32_set(struct task_struct *target,
			 const struct user_regset *regset,
			 unsigned int pos, unsigned int count,
			 const void *kbuf, const void __user *ubuf)
{
	int ret = 0;
	if (kbuf) {
		const compat_ulong_t *k = kbuf;
		while (count > 0 && !ret) {
			ret = putreg32(target, pos, *k++);
			count -= sizeof(*k);
			pos += sizeof(*k);
		}
	} else {
		const compat_ulong_t __user *u = ubuf;
		while (count > 0 && !ret) {
			compat_ulong_t word;
			ret = __get_user(word, u++);
			if (ret)
				break;
			ret = putreg32(target, pos, word);
			count -= sizeof(*u);
			pos += sizeof(*u);
		}
	}
	return ret;
}

long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
			compat_ulong_t caddr, compat_ulong_t cdata)
{
	unsigned long addr = caddr;
	unsigned long data = cdata;
	void __user *datap = compat_ptr(data);
	int ret;
	__u32 val;

	switch (request) {
	case PTRACE_PEEKUSR:
		ret = getreg32(child, addr, &val);
		if (ret == 0)
			ret = put_user(val, (__u32 __user *)datap);
		break;

	case PTRACE_POKEUSR:
		ret = putreg32(child, addr, data);
		break;

	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
		return copy_regset_to_user(child, &user_x86_32_view,
					   REGSET_GENERAL,
					   0, sizeof(struct user_regs_struct32),
					   datap);

	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
		return copy_regset_from_user(child, &user_x86_32_view,
					     REGSET_GENERAL, 0,
					     sizeof(struct user_regs_struct32),
					     datap);

	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
		return copy_regset_to_user(child, &user_x86_32_view,
					   REGSET_FP, 0,
					   sizeof(struct user_i387_ia32_struct),
					   datap);

	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
		return copy_regset_from_user(
			child, &user_x86_32_view, REGSET_FP,
			0, sizeof(struct user_i387_ia32_struct), datap);

	case PTRACE_GETFPXREGS:	/* Get the child extended FPU state. */
		return copy_regset_to_user(child, &user_x86_32_view,
					   REGSET_XFP, 0,
					   sizeof(struct user32_fxsr_struct),
					   datap);

	case PTRACE_SETFPXREGS:	/* Set the child extended FPU state. */
		return copy_regset_from_user(child, &user_x86_32_view,
					     REGSET_XFP, 0,
					     sizeof(struct user32_fxsr_struct),
					     datap);

	case PTRACE_GET_THREAD_AREA:
	case PTRACE_SET_THREAD_AREA:
#ifdef CONFIG_X86_PTRACE_BTS
	case PTRACE_BTS_CONFIG:
	case PTRACE_BTS_STATUS:
	case PTRACE_BTS_SIZE:
	case PTRACE_BTS_GET:
	case PTRACE_BTS_CLEAR:
	case PTRACE_BTS_DRAIN:
#endif /* CONFIG_X86_PTRACE_BTS */
		return arch_ptrace(child, request, addr, data);

	default:
		return compat_ptrace_request(child, request, addr, data);
	}

	return ret;
}

#endif	/* CONFIG_IA32_EMULATION */

#ifdef CONFIG_X86_64

static const struct user_regset x86_64_regsets[] = {
	[REGSET_GENERAL] = {
		.core_note_type = NT_PRSTATUS,
		.n = sizeof(struct user_regs_struct) / sizeof(long),
		.size = sizeof(long), .align = sizeof(long),
		.get = genregs_get, .set = genregs_set
	},
	[REGSET_FP] = {
		.core_note_type = NT_PRFPREG,
		.n = sizeof(struct user_i387_struct) / sizeof(long),
		.size = sizeof(long), .align = sizeof(long),
		.active = xfpregs_active, .get = xfpregs_get, .set = xfpregs_set
	},
	[REGSET_IOPERM64] = {
		.core_note_type = NT_386_IOPERM,
		.n = IO_BITMAP_LONGS,
		.size = sizeof(long), .align = sizeof(long),
		.active = ioperm_active, .get = ioperm_get
	},
};

static const struct user_regset_view user_x86_64_view = {
	.name = "x86_64", .e_machine = EM_X86_64,
	.regsets = x86_64_regsets, .n = ARRAY_SIZE(x86_64_regsets)
};

#else  /* CONFIG_X86_32 */

#define user_regs_struct32	user_regs_struct
#define genregs32_get		genregs_get
#define genregs32_set		genregs_set

#define user_i387_ia32_struct	user_i387_struct
#define user32_fxsr_struct	user_fxsr_struct

#endif	/* CONFIG_X86_64 */

#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
static const struct user_regset x86_32_regsets[] = {
	[REGSET_GENERAL] = {
		.core_note_type = NT_PRSTATUS,
		.n = sizeof(struct user_regs_struct32) / sizeof(u32),
		.size = sizeof(u32), .align = sizeof(u32),
		.get = genregs32_get, .set = genregs32_set
	},
	[REGSET_FP] = {
		.core_note_type = NT_PRFPREG,
		.n = sizeof(struct user_i387_ia32_struct) / sizeof(u32),
		.size = sizeof(u32), .align = sizeof(u32),
		.active = fpregs_active, .get = fpregs_get, .set = fpregs_set
	},
	[REGSET_XFP] = {
		.core_note_type = NT_PRXFPREG,
		.n = sizeof(struct user32_fxsr_struct) / sizeof(u32),
		.size = sizeof(u32), .align = sizeof(u32),
		.active = xfpregs_active, .get = xfpregs_get, .set = xfpregs_set
	},
	[REGSET_TLS] = {
		.core_note_type = NT_386_TLS,
		.n = GDT_ENTRY_TLS_ENTRIES, .bias = GDT_ENTRY_TLS_MIN,
		.size = sizeof(struct user_desc),
		.align = sizeof(struct user_desc),
		.active = regset_tls_active,
		.get = regset_tls_get, .set = regset_tls_set
	},
	[REGSET_IOPERM32] = {
		.core_note_type = NT_386_IOPERM,
		.n = IO_BITMAP_BYTES / sizeof(u32),
		.size = sizeof(u32), .align = sizeof(u32),
		.active = ioperm_active, .get = ioperm_get
	},
};

static const struct user_regset_view user_x86_32_view = {
	.name = "i386", .e_machine = EM_386,
	.regsets = x86_32_regsets, .n = ARRAY_SIZE(x86_32_regsets)
};
#endif

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
#ifdef CONFIG_IA32_EMULATION
	if (test_tsk_thread_flag(task, TIF_IA32))
#endif
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
		return &user_x86_32_view;
#endif
#ifdef CONFIG_X86_64
	return &user_x86_64_view;
#endif
}

void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
					 int error_code, int si_code)
{
	struct siginfo info;

	tsk->thread.trap_no = 1;
	tsk->thread.error_code = error_code;

	memset(&info, 0, sizeof(info));
	info.si_signo = SIGTRAP;
	info.si_code = si_code;

	/* User-mode ip? */
	info.si_addr = user_mode_vm(regs) ? (void __user *) regs->ip : NULL;

	/* Send us the fake SIGTRAP */
	force_sig_info(SIGTRAP, &info, tsk);
}


#ifdef CONFIG_X86_32
# define IS_IA32	1
#elif defined CONFIG_IA32_EMULATION
# define IS_IA32	is_compat_task()
#else
# define IS_IA32	0
#endif

/*
 * We must return the syscall number to actually look up in the table.
 * This can be -1L to skip running any syscall at all.
 */
asmregparm long syscall_trace_enter(struct pt_regs *regs)
{
	long ret = 0;

	/*
	 * If we stepped into a sysenter/syscall insn, it trapped in
	 * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP.
	 * If user-mode had set TF itself, then it's still clear from
	 * do_debug() and we need to set it again to restore the user
	 * state.  If we entered on the slow path, TF was already set.
	 */
	if (test_thread_flag(TIF_SINGLESTEP))
		regs->flags |= X86_EFLAGS_TF;

	/* do the secure computing check first */
	secure_computing(regs->orig_ax);

	if (unlikely(test_thread_flag(TIF_SYSCALL_EMU)))
		ret = -1L;

	if ((ret || test_thread_flag(TIF_SYSCALL_TRACE)) &&
	    tracehook_report_syscall_entry(regs))
		ret = -1L;

	if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))
		ftrace_syscall_enter(regs);

	if (unlikely(current->audit_context)) {
		if (IS_IA32)
			audit_syscall_entry(AUDIT_ARCH_I386,
					    regs->orig_ax,
					    regs->bx, regs->cx,
					    regs->dx, regs->si);
#ifdef CONFIG_X86_64
		else
			audit_syscall_entry(AUDIT_ARCH_X86_64,
					    regs->orig_ax,
					    regs->di, regs->si,
					    regs->dx, regs->r10);
#endif
	}

	return ret ?: regs->orig_ax;
}

asmregparm void syscall_trace_leave(struct pt_regs *regs)
{
	if (unlikely(current->audit_context))
		audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);

	if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))
		ftrace_syscall_exit(regs);

	if (test_thread_flag(TIF_SYSCALL_TRACE))
		tracehook_report_syscall_exit(regs, 0);

	/*
	 * If TIF_SYSCALL_EMU is set, we only get here because of
	 * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
	 * We already reported this syscall instruction in
	 * syscall_trace_enter(), so don't do any more now.
	 */
	if (unlikely(test_thread_flag(TIF_SYSCALL_EMU)))
		return;

	/*
	 * If we are single-stepping, synthesize a trap to follow the
	 * system call instruction.
	 */
	if (test_thread_flag(TIF_SINGLESTEP) &&
	    tracehook_consider_fatal_signal(current, SIGTRAP))
		send_sigtrap(current, regs, 0, TRAP_BRKPT);
}